Automatic telephone system.



A. B. SPERRY.

AUTOMATIC TELEPHONE SYSTEM.

,APPUCATION FILED JAN. 14. I916.

Patented Oct, 9, 1917. 2 SHEETS-SHEET 2 In yen for: A rzhur B Sperry.

" Amy.

ARTHUR BRUCE SPERRY, or NEW YORK, N. Y., ASSIGNOR To wnsfrnnn ELECTRICCOMPANY, INCORPORATED, or NEW YORK,1\T.Y.,A coaronn'rronor new YORK.

To all whom it may concern: Be it known that I, SPERRY, a citizen of theUnited States, residing at New York, in the county of New York and Stateof New York, have invented certain new and useful Improvements inAutomatic Telephone Systems, of which the following is a full, clear,concise, and eXact description. v v

This invention relates to telephone systerms in which the talkingconnections are established, in part at least, by means of automatic orelectrically actuated switching mechanism. I i

The invention is directed in general towardthe provision of a system ofthis charactor in which the impulses for controlling the switches usedin establishing a connection, are transmitted over the third ornontalking conductor of the connecting circuits, and more particularlyto a system of this character in which the test for idle trunks at theselector switches employed takes place through one of the brushes in thetalking circuit.

In the drawings, Figures 1 and 2, with Fig. 1 at the left,diagrammatically indicate the circuits and apparatus employed with thepresent invention.

The switches employed inthe present invention may be of any desiredkind, in which the switch brushes are firstmoved to select a group ofcontacts and are then moved over the contacts of the group to select aparticular set of contacts in the selected group. A switch of thisgeneral character is shown in the patent to Keith ct aZ., No. 815,176.In the following description of the present invention, however, therotary stepping magnet will be described asoperating first, that is, itis assumed that an around-and-up switch is em ployed in the presentsystem instead of the up-and-around'switch shown in said patent. Aswitch of this character is shown in an application to Oscar F.Forsberg, Serial No. 6,302,. filed February 5,v 1915. The side switchemployed in the present invention may also be of the type shown in saidForsberg application. .This side switch diifers from the one shown inthe Keith patent, principally in that its wipers may be caused to movein certain instances upon the energization instead of upon the denergization of its controlling magnet.

Specification of Letters Patent.

Application filed January 14, 1916. 7 Serial No. 72,139.

AR'rn R Biro on w armature of relay 11 to ground.

Patented Oct. 9,1917.

At the left in Fig. l of the drawings, the callingline 1 is shownjoinedto theconnecting circuit 2 by means of. a line finder switch.diagrammatically indicatedby the brushes 3, land 5. It is immaterial,however, in what. mannerthe calling line is joined to the trunk circuit.This could as well be accomplished by means of a line or trunk findingswitch or by means of a manually operated plug and jack switch, as thepresent invention may be as well employed in a semi-automatic telephonesystem as in a full automaticv system. Assuming now that the line finderbrushes 8, A and 5 are positioned on the contacts of the calling line 1and that'the side switch wipers 6, 7 and 8 have moved to position 41,the cutoff relay 9 will be energized by a-circuit extending throughbrush 3 and wiper 6, thus cutting off the line relay 10 of the callingnow closed at the hook-switch, current will j flow from grounded batterythrough the right winding of impulse relay 11, wiper 7, brush 4:, theleft side of the calling line, through the substation apparatus, backover the right side of the line, brush 5, wiper 8 and the left windingof relay 11 back to ground. Relay 11 will attract its armaturecompleting a circuit for the slow-release relay 12. i

The calling subscriber will now operate his dial to send the firstseries of impulses. The substation sender circuit may be substantiallyof the character shown in patent to A. E. Lundell, No. 1,1418,912,issued Au gust 3, 1915. The sender arrangement disclosed insaid patent,causes a series of interruptions in the line circuit and during thetimesuoh interruptions are being sent, short circuits the callingsubscribers receiver. With the first interruption in the line circuitrelay 11 will be deprived of our rent'and will retract its armature.completing a circuit from battery through the rotary stepping magnet 13and the escape magnet relay 14 in parallel and thence through thecontact and right armature of relay 15, side switch wiper 16, frontcontact and armature of relay 12, back contact and A circuit will alsobe provided for the relay 15, but due to the resistance 17 in serieswith the winding of this relay and also due' to the fact that itsarmatures are held. retracted by a relatively heavy spring, it will notbe energized during the brief periods its circuit is. closed at the backcontact of relay 11 during the operation of the sender. Relay 14 inattracting its armature completes a circuit from battery through theescape magnet 18, wiper 19 and the armature and contact of relay 14,causing the energization of the escape magnet. illelay-h is slow torelease and, therefore, holds up its armature throughout the series ofinterruptions in its circuit caused by the subscribers sending device.The rotary stepping magnet 13 is, however, repeatedly energized anddeenergized, thus stepping the selector switch brushes 20, 21 and 22from group to group of the trunk lines terminating at said switch.

At the termination of the series of impulses, the circuit of relay 11 ismaintained closed so that magnet 13 and relay 14 deenergize. The switchstops on the selected group of contacts, and as relay 1% retracts itsarmature due'to the prolonged interruptions of its circuit, the escapemagnet 18 becomes deenergized and moves the side witch wipers toposition 2.

In position 2 the test relay 23 is joined to the selector brush 21through wiper 2%. A circuit is also established for the test relay 23from battery through-relay 15, wiper 16, vertical ofi-normal contact 25,which opens on the first vertical step, and through the winding of relay23 to ground. A circuit is now closed from battery through the verticalstepping magnet 27, off-normal contact 28, wiper 29 and interrupter 30thus causing the-brushes 20, 21 and 22 to be stepped from set to set ofthe trunk contacts in the selected group. The test contact of busytrunks will be supplied with battery potential through the brush 21,wiper 2-1 and resistance 26 of the selector associated with said trunkat one of its multiple terminals and, therefore, the test relay will beheld up while brushes 20, 21 and 22 pass over busy trunks. lNhen theyengage the contacts of an idle trunk, battery will not be present uponthe contact engaged by brush 21, and relay 23 will fall off closing atits left armature and back contact the circuit for the escape magnet 18.The escape magnet will be energized, and in attracting its armature willmove the side switch to position 3.

The calling subscribers line is new connected through to the connectorswitch shown in Fig. 2. If desired, however, other selector switches,similar to the one shown to the right in Fig. 1, may be interposedbetween said selector switch and the connector switch of Fig. 2.

In the present disclosure, however, the calling subscriber will nowoperate his sending device to send out the next ortens series ofimpulses, each interruption at the sending device will cause theretraction of the armature of relay 11 as before. With the firstretraction of the armature of relay 11, a circuit will be completed frombattery through the rotary stepping magnet 101, wiper 102 and frombattery through the escape magnet relay 103 in parallel therewith andthence through the left armature and back contact of test relay 10%,back contact and right armature of relay 105, brush 20, wiper 16, frontcontact and armature of relay 12 and the back contact and armature ofrelay '11 to ground. Magnet 10land relay 103 will both be energized. Acircuit will also be established for relay 105, but as this relay ismade slow to pull up by providing its armatures with relatively strongretractile springs, it will not be affected by the brief currentimpulses therethrough by the operation of the sending device. Relay 103is made slow to release and holds up throughout the series of impulsesthereby maintaining an energizing circuit through its armature andalternate contact for the escape magnet 106.- The rotary stepping magnet101 isrepeatedly energized and deenergized, due to the impulses ofcurrent therethrough,- and steps the connectorswitch brushes 107, 108and 109 from group to group of the subscribers line contacts terminatingtherein until the tens group in which the wanted line terminatesisreached. The circuit for relay 11 will now be 1naintained closed, thusholding open the circuit, for stepping magnet 101 and relay 103; Relay103 will then retract its'armature and interrupt the circuit for theescape magnet 106 causing the side switch to move to posi tion 2.

The subscriber now operates the sending device to send the final orunits series of impulses. TVith the first retraction of the armature ofimpulse relay 11, circuits are closed through thevertical magnet 110andthe escape magnet relay 103in a manner similar to that in whichrotary magnet 101 and relay 103 were energized'when the tens series ofimpulses were sent. Relay 103 again closes the circuit for the escapemagnet 106 and maintains said magnet energized throughout the series ofimpulses. Vertical stepping magnet 110 is repeatedly energized anddeenergized, moving the brushes 107,108 and 109 from set to set of theline terminal contacts of the selected tens group.

When the connectorswitch brushes are positioned on the terminals of thecalled line, the calling substation circuit will re-- main closed at thesending device causing relay 11 to hold up its armature, thus holdin gopen the circuit of magnet 110 and relay 103. Relay 103 will retract itsarmature, but as its contacts are of themake-beforebreak character, thecircuit of theescape escape magnet 106 magnet 106 will be extendedthrough the normal contacts of relay 103, testrelay 10 1 and its normalcontact,wiper 112 and brush 107 to the test contact of-the wanted linen'We will first assume that the wanted line is busy, in which case thetest contact will be connected to earth through brush 107'and sideswitch wiper112 in positions 3 and 4: of the connector'switch associatedwith multiple contacts of the line. This beingthe case,'test-relay 104:will attract its armature, completing a locking circuit foritself .andin series through its right alternate contacts and side switch wiper 113to ground. The escape magnet will. thereupon be locked up, and the sideswitch wiperswill remain in position 2 until the switch is released andreturns to its normal position.

The escape magnet 106 being energized and the side switch being inposition 2, the busy tone device 114: is joined to the upper talkingstrand. It will be noted that this busy tone device was connected to theupper talking conductor while the last series of impulses was beingtransmitted, but as the calling subscribers receiver is short-circuitedduringthe sending of the impulses and as the connector side switch movesto position 3 simultaneouslywith the opening of this shunt circuit whenthe wanted sub- 'scribers line is idle, the calling subscriber in thatcase would not hear the tone.

" If the called line is busy, the calling subscriber will hear the busytone, and upon rep'lacing his receiver on the hook will open thecircuit-for relay 11. The armature of relay ll will' fall off" and willremainretracted completing a circuit from battery through theslow-to-pull up relay 105, brush 20 and wiper 16, also from batterythrough the slow-to-pull-up relay 15 and resistance 17, and thencethrough the front contact and its armature and front contact, thusinsuring the return of the selector switch to nor- 'mal position. Relay105 completes a circuit from battery through the release magnet 117,rotary ofi-normal contact 118, closed on first rotary step, frontcontact and leftarmature of relay 105 to ground. v Magnet 117 pulls upand locks through'cont'act 118 and its armature and contact, thuscausing the restoration of the connector switch;

If the wanted subscribers line'isidle, the contact engaged by brush/107will not be connected directly to groundas previously described and,therefore, relay 104 will not 1 be energized and magnet 106 will retractits armatures moving the side switch to position 3. A-circuitwillnow becompleted from battery through the escape'magnet .106,= armature andcontactof trip relay 119 and side switchwi'per 113 to ground. The escapemagnet attracts its armature, and

closesa-circuit from generator l20-through trip relay 119,contact andright armature of magnetx106, wiper 121,: brush 108,- the right side ofthe subscribers line, through the sub-5 stationbell, back over the leftside of the line, brush 109 and side switch wipers v122 and 113 toground' This causes the bell o the called substation to ring.

Upon the response of the calledsub-' scriber, the bell isshort-circuited causing an increased flow of current through relay 119,

which attracts its armature, thus interrupt- .ing the circuit for escapemagnet 106 and plied tothe called subscriber throughresistances 26and33. Y

The release of the-switches is controlled solely by the callingsubscriber, and when he interrupts his substation circuit'by replacinghis receiver upon the hook, relay 11 will fall off, after which releasewill take place in exactly the same manner as described in regard to anunsuccessful connection.

What is claimed is: a.

1. In a telephone'system, an electrically:

operated switch, a circuit extending to said switch, said circuitincluding a talking conductor and a non-talking conductor,meanscontrollable over said non-talking conductor for actuating said switchinestablishing a connection, and test means connected to said talkingconductor. a

'2. In a telephone system, an electrically operated switch, a'connectingcircuit extending to said switch, said connecting circuit comprising apair of talking conductors and a third or non-talking conductor, meanscontrollable over said third conductor for -actuating said switch inestablishing a connection, and test means connected toone of saidtalking conductors.

3.111 a telephone system, an incoming line, means including anelectrically operated switch for extending said line, a connectingcircuit extending to said switch, said connecting circuit comprising atalking conductorand a. non-talking conductor, means controllable oversaid non-talking conductor.for'actuating said switch in establlshingand-1n disestabhsh-ing a connection, andtest means connected to one ofsaid talking conductors.

4:. In a telephone system, an incoming line,- means including a selectorswitch for extending said line, a connecting circuit exten'dingto saidswitch, said circuit comprising a pair of talking conductors and a thirdor non-talking conductor, means controllable over said third conductorfor causing the movement of said switch in establishing a connection,means for determining the busy or idle condition of a circuit connectedto one of said talking conductors, and means for releasing said switchcontrollable over said third conductor.

5. In a telephone system, a subscribers line, means including aselector. switch for extending said line, a connecting circuit extendingto said switch, said circuit comprising a talking conductor and anon-talking conductor, a stepping magnet for said switch, means forjoining said magnet to said non-talking conductor, means fortransmitting impulses over said third conductor to said magnet tocause-the movement of said switch in establishing a connection and meansfor determining the busy or idle condition of a circuit arranged to beconnected with said talking conductor.

6. In a telephone exchange system, a con necting circuit, including atalking conductor and a non-talking conductor, a selector switch havingbrushes at which said conductors respectively terminate, groups of trunklines having terminals arranged to be engaged by said brushes, meansoperable by impulses over said non-talking conductor for moving saidbrushes from group to group of said trunk line terminals, and meansconnected to said talking conductor for controlling the operation ofsaid switch to select the terminals of an idle trunk line.

7. In a telephone exchange system, a con necting circuit, including atalking conductor and a non-talking conductor, a switch having brushesat which said conductors respectively terminate, groups of circuitterminals arranged to be engaged by said brushes, means operable oversaid non-talking conductor for moving said brushes from group togroup'of said extension circuit terminals, and meansconnectecl to'saidtalking conductor for determining the busy or idle condition of acircuit having its terminals engaged by said brushes.

8. In a telephone exchange system, a connecting circuit, comprising apair of talking conductors and a third or non-talking conductor, aselector switch having brushes at which said conductors respectivelyterminate, extension circuit terminals arranged in groups, meansoperable over said third conductor for moving said brushes to select agroup of said extension circuit terminals, means for causing saidbrushes to move a from circuit to circuit in the selected group torswitch having brushes ,at which said conductors respectively terminate,groups of extension circuits having terminals arranged to be engaged bythe brushes of said switch, means controllable over said non-talkingconductor for moving said brushes from group to group of the terminalsof said extension circuits, means for moving said brushes from setto setof the terminals in the selected group, a test relay, and a side switchhaving a wiper for oining said relay to one of said talking conductorsduring such last named movement.

10. In a telephone exchange system, a connecting circuit consisting of apair of talking conductors and a third or non-talking conductor, .aselector switch having brushes at which said conductors respectivelytern'iinate, groups of extension circuits having terminals arranged tobe engaged by the brushes of said switch, means controllable oversaidthird conductor for moving said brushes from group to group of theterminals of said extension circuits, means for moving said brushes fromset to set of the terminals in the selected group, a test relay, meansfor joining said relay to one 01 said talking conductors during suchlast named movement and means controlled by said relay for causing saidswitch to stop from set to set of the terminals in the selected group, aside switch, a circuit for said magnet including a wiper of said sideswitch, a test relay, a side switch wiper for joining said relay to oneof said talking conductors during such last named move ment, a magnetfor operating said side switch and a circuit for said side switch.magnet controlled by said relay.

12. In a telephone exchange system, a calling subscribers line,'meansincluding a selector switch for extending said line, a connectingcircuit including a pair of talking conductors and a third ornon-talking nals, means for moving said switch over conductor extendingto said switch, groups the terminals in a group, a test relay and ofextension circuit terminals, an impulse means for connecting said relayto said relay, means at the substation for controltalking conductors tocause said switch to 5 ling the operation of said impulse relay to stopwhen its brushes engage the terminals 15 transmit impulses over saidthird conducof an idle extension circuit. tor, an electro-magnetassociated with said In witness whereof, I hereunto subscribe thirdconductor and arranged to be actumy name this 13th day of January, A. D.

I ated by said impulses for moving said 1916.

1o switch from group to group of said termi- ARTHUR BRUCE SPERRY.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents,

Washington, D. 0.

